Biological Response Dynamics to Cochlear Implantation: Modeling and Modulating the Electrode–Tissue Interface

Ausili, Sebastián A.; Parreño, Matias; Fernandez, Florencia; Boccio, Carlos Mario; Lella, Federico Alberto Di

doi:10.1097/aud.0000000000001236

Cited by 3 publications

(1 citation statement)

References 48 publications

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“…Ongoing research aims to determine whether CI impedances can be biomarkers of traumatic intracochlear events and inflammatory responses ( Shaul et al 2019 ; Ausili et al 2022 ; Leblans et al 2022 ; Wimmer et al 2022a ). The basal turn of the cochlea is reported to be more exposed to severe intracochlear trauma and tissue reactions ( Seyyedi & Nadol Jr. 2014 ; Aebischer et al 2021 ; Rahman et al 2022 ).…”

Section: Discussionmentioning

confidence: 99%

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

et al. 2023

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Objectives: Reliable determination of cochlear implant electrode positions shows promise for clinical applications, including anatomy-based fitting of audio processors or monitoring of electrode migration during follow-up. Currently, electrode positioning is measured using radiography. The primary objective of this study is to extend and validate an impedance-based method for estimating electrode insertion depths, which could serve as a radiation-free and cost-effective alternative to radiography. The secondary objective is to evaluate the reliability of the estimation method in the postoperative follow-up over several months. Design: The ground truth insertion depths were measured from postoperative computed tomography scans obtained from the records of 56 cases with an identical lateral wall electrode array. For each of these cases, impedance telemetry records were retrieved starting from the day of implantation up to a maximum observation period of 60 mo. Based on these recordings, the linear and angular electrode insertion depths were estimated using a phenomenological model. The estimates obtained were compared with the ground truth values to calculate the accuracy of the model. Results: Analysis of the long-term recordings using a linear mixed-effects model showed that postoperative tissue resistances remained stable throughout the follow-up period, except for the two most basal electrodes, which increased significantly over time (electrode 11: ~10 Ω/year, electrode 12: ~30 Ω/year). Inferred phenomenological models from early and late impedance telemetry recordings were not different. The insertion depth of all electrodes was estimated with an absolute error of 0.9 mm ± 0.6 mm or 22° ± 18° angle (mean ± SD). Conclusions: Insertion depth estimations of the model were reliable over time when comparing two postoperative computed tomography scans of the same ear. Our results confirm that the impedance-based position estimation method can be applied to postoperative impedance telemetry recordings. Future work needs to address extracochlear electrode detection to increase the performance of the method.

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Section: Discussionmentioning

confidence: 99%

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

et al. 2023

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Improved intracochlear biopolymeric drug delivery system: an in vivo study

Goncalves,

Thielhelm,

Pawley

et al. 2024

Acta Oto-Laryngologica

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A Single Intratympanic Triamcinolone Acetonide Administration Elicits Long-Term Reduction in Impedances Following Cochlear Implantation

Nieratschker,

Liepins,

Honeder

et al. 2024

Journal of Otolaryngology - Head & Neck Surgery

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Background Intracochlear fibrosis and inflammation remain important limitations in cochlear implantation (CI). Glucocorticoids are routinely used to ameliorate the inflammatory response following CI. This study investigates the long-term effects of an intratympanically-applied triamcinolone-acetonide suspension on intracochlear impedance changes in CI recipients and investigates differences in drug concentrations and timepoints of injection. Methods A total of 87 patients were included in the study, of whom 39 received an intratympanically-applied triamcinolone-acetonide suspension at either 10 or 40 mg/ml, 1 hour or 24 hours prior to cochlear implantation, while 48 patients served as an untreated control group. Electrode impedances were measured and compared over a period of 3 years following cochlear implantation. Results The preoperative intratympanic application of a triamcinolone-acetonide suspension resulted in significantly lower mean impedances following cochlear implantation compared with an untreated control group at first fitting (4.66 ± 1.3 kΩ to 5.90 ± 1.4 kΩ, P = .0001), with sustained reduction observed over 3 months. A sustained reduction was observed after spatial grouping of the electrode contacts, with significant improvements in both the middle cochlear region over a 24 month period (from 3.97 ± 1.3 kΩ to 5.85 ± 1.3 kΩ, P = .049) and the basal region over a 6 month period (from 5.02 ± 1.3 kΩ to 5.85 ± 1.3 kΩ, P = .008). The injection of 10 mg/ml of triamcinolone-acetonide 1 hour prior to cochlear implantation resulted in higher impedances compared with 40 mg/ml and 24 hour time interval until surgery. Conclusion A single preoperative intratympanic injection of triamcinolone-acetonide significantly reduces electrode impedances across the entire cochlea. This effect is sustained for up to 2 years, after which impedances gradually equalize between the groups. A preoperative triamcinolone-acetonide injection could therefore be a favorable approach to attenuate the immediate tissue response following cochlear implantation.

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Biological Response Dynamics to Cochlear Implantation: Modeling and Modulating the Electrode–Tissue Interface

Cited by 3 publications

References 48 publications

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

Improved intracochlear biopolymeric drug delivery system: an in vivo study

A Single Intratympanic Triamcinolone Acetonide Administration Elicits Long-Term Reduction in Impedances Following Cochlear Implantation

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